A LDPC (Low Density Parity Check) code is a linear error correcting code and is another important code after the Turbo code. A check matrix of the LDPC has a property of sparse, thus an encoding method and a decoding method of the LDPC are not complex. Moreover, a decoding of the LDPC has a property of parallel which is in favor of designing a high-throughput decoder. The LDPC possesses properties, such as good flexibility, low error probability and high throughput, therefore, the LDPC has been adopted by various standards, such as the IEEE802.11n and the DVB-S2 standards.
However, there is a problem of low spectrum efficiency in existing methods for transmitting data using LDPC code.